#define _CRT_SECURE_NO_WARNINGS 1
class Solution {
public:
    int dx[4] = { 0, 0, 1, -1 };
    int dy[4] = { 1, -1, 0, 0 };
    int m, n;
    int memo[301][301];
    int longestIncreasingPath(vector<vector<int>>& matrix)
    {
        m = matrix.size(), n = matrix[0].size();
        int ret = 0;
        for (int i = 0; i < m; i++)
            for (int j = 0; j < n; j++)
            {
                ret = max(ret, dfs(i, j, matrix));
            }
        return ret;
    }

    int dfs(int sr, int sc, vector<vector<int>>& matrix)
    {
        if (memo[sr][sc] != 0) return memo[sr][sc];

        int ret = 1;
        for (int k = 0; k < 4; k++)
        {
            int x = sr + dx[k], y = sc + dy[k];
            if (x >= 0 && x < m && y >= 0 && y < n && matrix[x][y] > matrix[sr][sc])
            {
                ret = max(ret, dfs(x, y, matrix) + 1);
            }
        }
        memo[sr][sc] = ret;
        return ret;
    }
};